title: Increased thymosin β4 levels in the serum and SF of knee osteoarthritis patients correlate with disease severity.
abstract: OBJECTIVE
  Thymosin β4, a member of a large family of thymic proteins, plays an important role in the process of articular cartilage degeneration which is a common cause of osteoarthritis (OA). This study aims to determine thymosin β4 levels in the serum and synovial fluid (SF) of patients with knee OA and analyze the correlation of thymosin β4 levels with the radiographic severity of OA.
  
  
  METHODS
  This study consisted of 216 patients with knee OA and 152 healthy controls. OA progression was classified based on Kellgren-Lawrence by evaluating x-ray changes observed in anteroposterior knee radiography. Thymosin β4 levels in the serum and SF were measured by enzyme-linked immunosorbent assay method.
  
  
  RESULTS
  The knee OA patients had higher levels of serum thymosin β4 than the healthy controls. Knee OA patients with KL grade 4 showed significantly elevated thymosin β4 levels in the serum and SF compared with those with KL grades 2 and 3. Knee OA patients with KL grade 3 had significantly higher SF levels of thymosin β4 than those with KL grade 2. Thymosin β4 levels in the serum and SF of knee OA patients were significantly correlated with disease severity according to KL grading criteria.
  
  
  CONCLUSIONS
  The thymosin β4 levels in the serum and SF may serve as effective biomarkers for the severity of OA.
authors.affiliation: Department of Orthopaedics, General Hospital of Chinese People's Liberation Army, Beijing, PR China. Electronic address: bjweimin12@126.com.
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: Dongmei
authors.initials: D
authors.lastname: Duan
authors.forename: Yujie
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhongli
authors.initials: Z
authors.lastname: Li
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000378:metabolism*; D013947:Thymosin / Q000097:blood*; D000099201:Thymosin beta(4)
chemical_list: D015415:Biomarkers; D013947:Thymosin; D000099201:Thymosin beta(4)
keywords: Osteoarthritis; Serum; Severity; Synovial fluid; Thymosin β4